= Result

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INSTRUCTION

In order to calculate the sum of all integer numbers between values Min and Max (inclusive), follow the steps:

1. Enter the smallest number in text box marked "Min"
2. Enter the biggest number in text box marked "Max"
3. Click the on-screen button "=" to get the result

The task could be completed using either the iterations (looping), or by applying the exact formula for arithmetic progression shown below:

SUM = (Min + Max)*(Max-Min+1)/2

For example, the SUM of all integer numbers between 1 and 10 could be calculated as:

SUM = (1 + 10)*(10-1+1)/2 = 55

For practice purpose, check the answer using Excel spreadsheet.